1. Field of the Invention
The present invention relates to a process for preparing polyhydric phenol compounds represented by the formula (I): ##STR3## wherein R.sub.1, R.sub.2 and R.sub.3 represent independently hydrogen atom, alkyl, alkenyl, cycloalkyl, aralkyl or aryl group, which are useful as an intermediate of photosensitive agents or sensitizers for photoresists and the like.
2. Related Art
As a method for preparing phenylchroman derivatives which have a structural resemblance to polyhydric phenol compounds, U.K. Patent No. 822,659 discloses a process comprising reacting resorcinol with acetone in a molar ratio of 2:3.about.2:1 in the presence of an inorganic acid by using water as reaction solvent. This process, however, has a problem that it is unable to produce a polyhydric phenol compound with high purity in a high yield when it is applied to a condensation reaction of a compound represented by the formula (II): ##STR4## wherein R.sub.1, R.sub.2 and R.sub.3 are as defined above, with pyrogallol.
An object of present invention is to overcome the above problem and provide an industrially advantageous process for producing the polyhydric phenol compounds.